Pyrolysis Reactor Pressure Control for Tire Carbon Quality
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Solution Overview
Problem
Existing carbonization processes for converting old tires into carbon products are energy-intensive, leading to suboptimal carbon quality and increased operational costs, despite previous attempts to reduce temperatures and improve efficiency.
Innovation Solution
A medium-temperature pyrolysis system with a cylindrical reactor vessel heated to 420°C-620°C, featuring a gas discharge line with cooling coils, a pyrolysis oil collection tank with two chambers, and a control unit that maintains constant system pressure below 60 mbar, ensuring a constant volume flow and increased residence time of pyrolysis gas, thereby reducing energy consumption and improving carbon quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperatures (above 580°C) are used in pyrolysis, then carbon quality improves, but energy consumption increases significantly
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperatures (>580°C) to medium temperatures (450-620°C), and modifies the pressure parameter by maintaining vacuum conditions throughout the process. This combination of parameter changes achieves high carbon quality (BET surface area ≥200 m²/g) while significantly reducing energy consumption, directly resolving the technical contradiction between carbon quality and energy use.
Solution Approach 2:
The patent maintains a vacuum atmosphere (inert environment) throughout the pyrolysis process by continuously evacuating the reactor. This prevents oxidation and combustion of carbonaceous materials, allowing pyrolysis to proceed at lower temperatures without sacrificing carbon quality, thereby reducing energy consumption while maintaining manufacturing precision.
2Use of energy by moving object
If medium temperatures (450-620°C) are used to reduce energy consumption, then energy efficiency improves, but carbon quality may deteriorate
Solution Approach 1:
The patent combines medium temperature (450-620°C) with vacuum pressure conditions, creating a unique parameter combination that enables high carbon quality at lower temperatures. The vacuum environment prevents side reactions and promotes complete pyrolysis, ensuring BET surface area ≥200 m²/g even at 450-620°C, thus resolving the contradiction between energy efficiency and carbon quality.
Solution Approach 2:
The patent creates a composite process condition combining thermal energy (medium temperature) with mechanical energy (vacuum evacuation). This composite approach allows the system to achieve high carbon quality through the synergistic effect of moderate heating and continuous gas removal, preventing re-condensation and promoting complete decomposition at lower temperatures.
3Reliability
If vacuum conditions are maintained throughout pyrolysis, then pyrolysis gas is continuously removed preventing combustion, but system complexity increases
Solution Approach 1:
The patent implements continuous vacuum evacuation throughout the entire pyrolysis process, maintaining inert conditions without interruption. This continuous action ensures complete removal of pyrolysis gases, preventing any combustion reactions. The simplicity of this continuous approach outweighs the initial complexity, as it eliminates the need for complex multi-stage pressure control systems.
Solution Approach 2:
The vacuum system serves multiple functions simultaneously: it removes pyrolysis gases to prevent combustion, maintains inert atmosphere for complete decomposition, and facilitates heat transfer. This self-service capability reduces the need for additional separate systems, thereby limiting the increase in device complexity while achieving reliable combustion prevention.
4Manufacturing precision
If residence time of pyrolysis gas in reactor is increased, then carbon quality improves, but processing time increases
Solution Approach 1:
The patent extends residence time to 1-24 hours, which is significantly longer than conventional processes. This extended duration allows complete decomposition of carbonaceous materials and formation of high-quality carbon with BET surface area ≥200 m²/g. The continuous vacuum evacuation prevents side reactions during this extended period, making the additional processing time worthwhile for achieving superior carbon quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in significant energy savings, improved carbon quality for industrial soot refinement, enhanced pyrolysis oil viscosity and cleanliness, and reduced coke formation, while maintaining the quality of carbon products.
Implementation Method 1
at least one cooling coil (3) connected to said gas exhaust line (2) for condensing the pyrolysis oil
Implementation Method 2
a compressor (6) located downstream of said gas collector (5), by which a constant or nearly constant volume flow of the pyrolysis gas from the reactor vessel (1) is set at a constant or nearly constant system pressure
Implementation Method 3
a cylindrical reactor vessel (1) which can be heated in a pyrolysis oven to a temperature of up to 620° C.
Implementation Method 4
heating elements, wherein the control unit (13) is coupled with at least one temperature sensor (7) for determining the pyrolysis gas temperature
Data Source
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AI summary
The invention relates to a device for carrying out a steam cracking process, comprising: a cylindrical reactor vessel (1) which can be heated in a pyrolysis furnace to a temperature of up to 650°C and which is open to the top and can be closed by a cover in the form of a domed base, the cover having a gas exit opening that can be connected to a gas off-take line (2) from the pyrolysis furnace and below the cover at least one perforated baffle plate being supported on the reaction vessel inner wall; at least one cooling coil (3) for condensing the pyrolytic oil, which is connected to the gas off-take line (2); at least one pyrolytic oil collection container (4) mounted downstream of the cooling coil; and a gas collector (5) for the remaining gas; and a control unit (13) for the open-loop and closed-loop control of the heating temperature. The control unit (13) is coupled to at least one temperature sensor (7) for measuring the pyrolysis gas temperature in the gas off-take line (2) close to the exit of the gas off-take line (2) from the pyrolysis furnace. A compressor (6) is mounted downstream of the gas collector (5) and adjusts, regulated by the control (13), a constant or near-constant volume flow of the pyrolysis gas from the reactor vessel (1) at a constant or near-constant system pressure once a predetermined pyrolysis gas temperature is reached and detected by the temperature sensor (7).